The invention relates to the fabrication of artificial dentures and more particularly to the formation of the denture directly in the patient's mouth.
The procedure normally used to produce dentures starts with an impression of the edentulous gums from which a stone or plaster model is formed. Base plates are added to the models and they are mounted on an articulator. Teeth are mounted on the models using wax and the proper bite is established. The teeth in wax are then tried in the patient's mouth to confirm the fit and bite. Once confirmed the try-in is remounted on the model and a plaster cast of the wax model is made. Using well known procedures, dental base material is poured in the plaster mold and cured, forming a denture. All surfaces of the denture are then cleaned and polished.
This procedure may require the patient to make several visits to the dentist for molds to be made, the try-in to be tested and finished dentures to be fitted and adjusted. Because of the numerous steps required to produce a finished denture by this method and the possible inaccuracies in fit inherent in the process many dentures formed in this manner are not satisfactory.
Several patents heve addressed these problems by proposing devices and procedures for forming a denture directly in the patient's mouth. Key among these patents are U.S. Pat. Nos. 3,460,252, 3,621,575, 3,838,513 and 4,345,900. Each of these patents use a specially designed tray which is formable in some manner. U.S. Pat. No. 3,460,252 incorporates a silicone rubber to hold the teeth in the tray and a plastic film over the tray during forming of the denture to protect the tissue from possible harm by harsh chemicals used to form the denture. U.S. Pat. No. 3,621,575 utilizes a similiar tray and a shim conforming to the tray. U.S. Pat. No. 3,838,513 also uses a similar tray holding the teeth. The tray is filled with alginate with a spacer placed thereon and an impression of the edentulous gums are taken. Upon removal of the alginate impression from the mouth the alginate must be removed from the root portion of the teeth in the tray prior to adding the denture forming material. U.S. Pat. No. 4,345,900 is directed to a special formable tray readily shaped to the patient's mouth. This conformed tray is then used to form dentures using previously described methods such as in U.S. Pat. No. 3,621,575.